The Tories released a television ad on Tuesday, claiming newly released documents show Wynne was briefed on Project Vapour, the Liberals' code name for the cancelled gas plants.
The new premier has said she was not at the table when decisions were made to cancel the two projects, which cost Ontario taxpayers an estimated $230 million.
Wynne was the party’s campaign co-chair in 2011, when the Mississauga gas plant was halted in mid-construction just days before the Oct. 6 election that year.
The Tories’ ad questions whether Wynne has chosen to forget she was part of the decision making to cancel the gas plants, and says governments should take responsibility for their actions.
The Tories released the ad just hours before Wynne's first throne speech, which Liberal sources said will reach out to the opposition in an effort to find common ground.
Wynne has already agreed to a Tory demand for a legislative committee to review all the decisions surrounding the gas plants.